Traffic signal



Aug- 5, 1941-v T. E. sTElBER 2,251,50/4

TRAFFIC SIGNAL Filed June 22, 1937 2 sheets-Sheet 1 AAug. 5, 1941. T.sTElBER TRAFFIC SIGNAL Filed Jun 22, 1.937

Fig. 3

2 Sheets-Sheet Patented Aug. 5, 1941 TENT OFFICE TRAFFIC SIGNAL TheodoreE. Steiber, Bridgeport, Conn., assignor of one-half to Arthur A.Johnson, Bridgeport,

Conn.

Application June 22, 1937, Serial No. 149,574- 12 Claims. (Ci. 177-337)This invention relates to a signal device and more particularly to thetype of device for controlling traiiic.

In current systems of operating traffic lights, a yellow caution signalis displayed to indicate a change of light from stop to go, or go tostop This signal does not indicate how soon or how much time is left forthe go or stop signal to remain lighted. A 4driver approaching theintersection has no means of telling whether the caution signal has beendisplayed for only a short time or Whether its period of operation isabout terminated, and does not know whether he can proceed through thesignal or whether he should stop.

According to the present invention, a signal is provided in which thestop and the go lights are operated in the predetermined manner so as toindicate to a driver approaching the intersection that the lights arechanging and approximately the amount of change that has taken place.

Preferably, according to the present invention, a plurality of lightsare used to illuminate each signal; All of these lights are lightedduring the period in which the stop or go signal is displayed. Duringthe interval when it is desired to change the lights the individuallights in at least one of the signals will be extinguished seriatim.rThis indicates to the operator of an automobile approaching theintersection that a certain portion of the changing time has elapsed andgives him a fairly accurate idea when the other signal will be displayedand become controlling.

According to the present invention, the go signal on one side of theframe, for example north and south, is connected to the stop signal onthe east and west and vice versa. The circuits for these signals arecontrolled by a means which will be operated only during the period inwhich a change in signal is to be made and which will cause the lightsto extinguish seriatim in one set of signals and at the end of theseriatim operation cause all of the light sources in the other set ofsignals to be immediately flashed on.

It will be obvious that this operation will tend to decrease the numberof traic accidents which occur due to the operator failing to know thatthe caution light has been displayed for a long period and that thesignal is about to change.

Care must be taken in using this mode of operation that the controllingmeans must function accurately for each operation. Accordingly, anelectro-magnetically operated latch may engage the contact drumcontrolling the operation of the lights or some portion of its drive andprevent the drum from over'running so that the period of operation isalways uniform and regular.

Further features and advantages will be apparent from the followingspecification taken in connection with the drawings.

In the drawings:

Figure 1v shows a perspective View of the traffic signal.

Fig. 2 shows a diagrammatic View of the traffic signal lights and thecontrolling circuit therefor.

Fig. 3 shows a vertical section of the traffic light.

Fig. 4 shows adetailed View of the controlling mechanism with the latchomitted.

Fig. 5a shows a developed plan view of the surface of the contact drumshowing the positions of the conta/cts thereon.

Fig. 5b is a developed plan view of the surface of a modification of thecontact drum for use with signal lamps adapted to be connected inparallel.

The traffic light according to the present invention is shown asembodying one for use with a two-way intersection. It is obvious thatthe light may be designed for any number of intersections. Y Thepreferred form of .the trahie signal herein disclosed comprises ahousing I0 adapted to be suspended or supported in any desired manner.The housing I0 has a generally horizontally extending portion I I.Secured to the underside of portion II and depending therefrom is avertically extending portion I2 of narrower dimensions, as shown in Fig.3. The upper portion II of the housing is provided with horizontallydisposed apertures I3 one for each approaching lane of traffic. Thelower portion I2 of the housing has a plurality of vertically disposedapertures I4 one for each approaching lane of traic. A stop signal I5for controlling traic, for example in an east-west direction, is mountedin the housing and comprises three light sour-ces or signalling unitsIa, I5b and I5c, as shown in Fig. 2. A stop signal I6 also mounted inthe upper portion II for controlling trailic in the north-southdirectionand comprises three light sources or signailing units IBa, I6band Hic.

The light sources herein disclosed are preferably luminous gaseousdischarge tubes although other signalling means may be used in order toobtain the desired result. These tubes are constructed so as -to begenerally Ushaped, the legs of the U being positioned behind theopposite apertures in the walls of the upper portion Il and the sectionof the tubes between the legs of the U being made with a slighttransverse bend, as shown in Fig. 3, so that all of the tubes may bepositioned in the casing with the legs or signalling portions disposedin the same general horizontal plane ehind the apertures. These tubesare mounted in the casing on a plurality of sup-ports il' which extendbehind the operative legs of the tubes and hold them in a position to bedisplayed or to illuminate the signalling aperture. The supports Il havean extension l projected up in back of the tubes to shield the same fromlighting up apertures opening in the opposite direction. These surfacesi3 are finished so as to produce a light-reflecting surface for thetubes. ln each corner ofthe frame, as shown in Fig. 2, a partition it*is provided connecting the supports and shielding members to the frameto prevent the light from giving a false signal to trafiic coming in theopposite direction. The portion of the tubes extending between theoperative legs of the U may be rendered opaque by coating them withsuitable material to also prevent them from giving a false signal.

The depending portion I2 of the housing IU contains a signal 2t forcontrolling the east-west traffic and comprising tubes Or signallingunits 2te, 2th and 2Go. A signal 2| is also provided in housing portionI2 for controlling traic in the north-south direction and comprisestubes or signalling units 2 la, 2 ib and 2 lc. These tubes arepreferably luminous gaseous discharge tubes although any suitablesignalling means may be used in place thereof. These tubes are formed inthe shape of a U and are nested one within the other as shown in Figs. 2and 3. The legs of the U, as shown in Fig. 2, are positioned behind theopposite apertures in the housing |2 and are shielded from one anotherby a plurality of shields 22 which prevent the giving of false signalsand which also form reiiecting surfaces for the tubes.

Mounted in the upper portion of the housing l| is a supporting frame 23upon which is secured a plate 2li. The plate extends over the area ofthe upper section and provides an adequate mounting for the necessarymechanism for energizing and controlling the lights. A transformer 25for energizing the luminous gaseous discharge tubes is mounted on theplate so as to be carried by the unit. The mechanism for controlling thevarious tubes so as to give the desired signals as will be more fullyexplained is also mounted on this plate. A dome 40 is secured to the topof the housing so as to overlie the top of the upper portion and isprojected upwardly to provide ample space for the transformer andcontrol unit for the light. In an upwardly projecting portion at thecenter of the dome is an insulating bushing lll of rubber or similarinsulating material which will make a water-tight bushing through whicha pair of leads i2 for the transformer and a pair of leads i3 for themotor are carried. These leads are the only ones which need be connectedto the trahie light. The leads from the motor go to the usual controlbox 55 containing mechanism comprising a switch for closing the circuitto the motor whenever it is desiredY to change signals and to display acaution signal during the interval between the change to warnapproaching drivers that the signal is about to change.

According to the present invention, the lights in the signals are sooperated as to indicate to the driver approaching the intersection theinterval of time in general that has elapsed since the caution signalhas been initiated so that he may determine whether or not be shouldproceed or stop,

In the preferred form of the present invention, the stop lights facingtrafiic in one direction are connected to operate with the go lights inthe other direction and vice versa so that these signals will operatetogether.

The desired control for the lights may take various forms such as relaysystems and the like, but according to the persent invention it isachieved by employing a drum 38 having stepped contact surfaces 39thereon. This drum is mounted on a shaft 31 supported by a supportingbracket 21 mounted on plate 24 and is driven from a motor 26, alsomounted on plate 24. The motor has a worm 3| secured to its shaft andcooperates with a worm gear Si] on a shaft 29 supported in a pair. ofbearings 28 of the supporting bracket 21. The shaft 29 has securedthereto a friction plate 32. Mounted to slide on the shaft 29 is asleeve carrying a plate 33 having a friction face 34. The plate 33 isspring pressed so that its friction face cooperates with the plate 32 toform a slip connection between the motor and the drum. The sleeve hasmounted thereon and rotating therewith a worm 35 meshing with a wormgear 35 on the shaft ill which carries the contact drum. As shown in thepresent invention, the drum will turn during one change of lights. Thishowever is optional and may be varied to suit varying conditions, forexample the drum may make one revolution to accomplish the same resultby having contacts extend around the entire surface.

An insulating block 44 is carried by the supporting bracket 2l. Acontactor is mounted on the block and extends into cooperative relationwith the drum to control one set of lights. This contactor comprisesthree insulated contacts 45a, 5b and 45o which engage the drum at theunder surface thereof. A second insulating block 46 is carried by thesupporting bracket and has mounted thereon a contactor comprisinginsulated contact elements 47a, 47h and 47o which engage the uppersideof the drum 180 from contacts 45a, 45h and 45o and control the other setof lights.

As shown in Fig. 2 the pairs of tubes 29a, and 2id, 2th and 2|b, and 20cand 2|c are connected at one end respectively to one side of each of thethree secondary windings of the transformer and the said tubes areconnected at their other ends in the following manner. The threehorizontal red east-West tubes |511., |519A and |5c are connected inseries with the vertical green north-south tubes 2 la, 2 Ib` and 2 |c,and the three horizontal northsouth'red tubes Ita, |611 and Ic areconnected with the three vertical green east-west tubes 20a, 2Gb and2SC. It will be seen, therefore, that when connected in this manner thestop light on one side of the frame or housing operates with the golight on the opposite side of the frame. The tubes are connected to thecontacts which when engaging the Contact portions 39 of the control drumin such a manner so as to close the circuits to the tubes, the contact45a is connected to and controls the tubes |5a and 2|a so that theyoperate at the same time. Contact @55a is connected to the tubes |5bland 2lb and contact d50 is connected to |50 and 2|c so that each pairoperate together. Similarly contact 47a is connected to tubes la and20a. Contact Bib is connected to tub-es |611 and 2lb and 41C isconnected to tubes 16e and Zlc. From the above connections, it will beseen that when the separate contacts close the circuit to thetransformer through contacts 39 the pairs of tubes connected theretowill be energized.

A developed plan view of the drum for controlling the lights accordingto the present invention is shown in Fig. 5a. The contact surfacesformed on the drum extend through 180 so that one half of a revolutionof the drum Will complete a change of lights. The Contact surface isformed with a short section 30a which will engage the contact brushes ldand t'l'a for approximately 60 of rotation of the drum. Contact 30?)extends further and will engage contacts 52) and ilb ior a period ofabout 120 of rotation of the drum. Contact 30C extends for slightly lessthan 100 of the drum to insure that the lights are extinguished beforethe other set iiashes on. This Contact engages contacts te and llc forapproximately the full length of time required in changing the signal.Contacts 30x, integral respectively Iwith contacts 39u, b, and c, extendaround the entire circumference of the drum and engage contacts dalwhich connect the contacts on the drum respectively to one side of eachof the secondary transformer windings. It will be seen that when thedrum is in the position shown in Fig. 2, a circuit will be closedthrough all of the light sources in signals i5 and 2l. When it isdesired to change the signal from go to stop, or stop to go, thecontroller in the usual control box 55 is operated to close the circuitto the motor which causes the drum tc rotate in the direction of thearrow, 2. As the drum rotates, contact 65a will leave the Contactsuriace after 60 of rotation of the drum and will cause signal lights Iaand Zia to be extinguished. Continued rotation of the drum for anotherdistance of 60 will cause contact @5o to leave the contact surface andwill cause the lights b and Zib to become extinguished. Further rotationof the drum for another 00 will cause the contact idc to leave thecontact surface and extinguish the lights itc and le. As the drumContinues to move, the Contact surface will immediately engage all ofthe contacts fil* to cause all of the lights associated therewith to beenergized. rThe inode of operation may be summed up as follows: When itis desired to change the traiicic signal from stop to go, or go to stop,the lights being displayed in the Various directions will be caused tobe ex inguished seriatim and immediately upon extinguishing the lastlight ci one signal, for example the go signal, the entire stop signalon that signalling side flashes on. This operation gives an oncomingmotorist an indication of the amount oi time elapsed from the beginningof the caution period so that he can decide instantaneously whether tostop or Whether he can pass the light before the signal changescompletely.

Fig. 5b shows a developed plan View of a drum 3B having a modiiedarrangement of stepped contacts thereon, adapted to replace drum 38providing that the luminous gaseous discharge tubes are replaced bylight sources adapted to be energized in parallel, such as, forinstance, incandescent lamps.

When this is the case, the multiple secondary transformer may beomitted, one power lead ft2 being connected to the Contact 5t while theother power lead i2 is connected to one terminal of each of thevertically disposed light sources 20a, b, and c, and 2id, b, and c.Connections from contacts 45a', b', and c' and contacts 41a', b', and cto light sources l5 and I6 are the same as those shown in Fig. 2 betweenthe said light sources and contacts 45a, b, and c, and 41a, b, and c.

Contact surfaces 30a', b', c', and are spaced respectively to extendover about 60, about 120, slightly less than and 360 of thecircumference of drum 30 in the same manner as contact surfaces 39a, h,c, and r of drum 38.

Operation of the signal by rotation of drum 30 is the same as in thecase of drum 38 in Fig. 5a.

With the caution signal oi the type disclosed in the present invention,care must be taken to prevent the drum from overrunning since such anoccurrence would cause the caution signal to be ineflicient for thepurpose designed, namely, to give an indication oi the elapsed time ofthe caution period. Accordingly, means have been provided for preventingsuch an occurrence. A 'pair'of pins 43 are positioned on the worm gear35, 180 apart and in deiinite spaced relation with respect to thecontact surfaces 39. A lever 50 is Ypivoted intermediate its ends to thesupporting bracket 2l to a pivot 5i. One end of the lever has a hoekportion adapted to engage the pins on the gear and prevent the gear fromfurther rotation. The other end of the lever is weighted to cause thelever to normally move into hookengaging position. The latter end of thelever is connected to a core 53 operating in a solenoid E9. The solenoidis connected in series in the motor circuit so that when the circuit isclosed to the motor by the control switch 55, the initial surge ofcurrent will be suicient to raise the core and to release the hook fromthe pin and, as the motor starts to rotate and move the drum and thestarting current decreases, the weight of the lever will be suiiicientto cause the hook to move into position to engage the next pin @.3 onthe gear which rotates the drum to hold the drum in a denite position.The slip coupling between the motor and the drum permits the motor tooverrun without affecting the drum. If desired the solenoid; may beconnected in a separate circuit to the control box 'to be controlledtherefrom instead of from the motor circuit as above described.

It will be seen that the drum can only make one half of a revolution foreach energization of the motor. If it is desired to alter the length oftime required to change from one signal to another, as on highways wherehigh speed requires a longer changing period, the gearing between themotor and the drum may be changed or the speed at which the motoroperates may be altered. k

Variations and modifications may be made within the scope of thisinvention and portions of the improvements may be used without others.

I claim:

1. In a signaling device comprising a housing having a stop and a goaperture, a plurality of light sources for illuminating each aperture;means mounted in the housing for varying in a predetermined manner thenumber of said light sources which are illuminated in each apertureduring a change of the signal from stop to go to give a caution signal,said control means including a periodically driven rotary contact drum;a plurality Vof iixed contactors cooperating there- With to control theillumination of said light sources; and electro-responsive means forarresting rotation of the drum to prevent overrunning thereof uponcompletion of a change of said signal from stop to go on one side andfrom go to stop on another side.

2. In a signaling device comprising a housing having a plurality ofsides, each signaling side having a stop aperture and a go aperture, aplurality of light sources for illuminating each aperture; means forcontrolling said light sources in a predetermined manner throughout theperiod of changing of the signals, to give a caution signal whichindicates the extent of lapse of said changing period, said controlmeans including a rotary Contact drum, fixed contactors cooperatingtherewith to control the illumination of said light sources in apredetermined manner, and electroresponsive means for rotating said drumduring a change of the signal from stop to go, and for arrestingrotation of said drum upon completion of such a change.

3. In a signaling device comprising a housing having a plurality ofsides, each signaling side having a stop aperture and a go aperture,means for illuminating the apertures comprising a plurality of lightsources for each aperture; means for controlling said light sources in apredetermined manner to give a caution signal including a rotary drumhaving stepped contacts thereon; iiXed contactors cooperating therewithto control the circuits of said light sources as the drum rotates; amotor for rotating the drum, periodically operated to change saidsignal; and means for limiting the rotation of the drum upon completionof a change of said signal from stop to go for each operation of themotor.

4. A signaling device comprising a housing having a plurality of sides,each signaling side having a stop aperture and a go aperture; means forilluminating the apertures comprising a plurality of light sources foreach aperture; control means for said light sources, including a rotaryinsulated drum having stepped contacts thereon, a plurality or" xedcontactors cooperating therewith to vary the number of light sourceswhich are illuminated in each aperture in a predetermined manner duringa change of the signal; a motor operated at predetermined intervals forrotating the drum; and means for limiting the amount of rotation of thedrum, including an electromagnetically operated latch for arrestingrotation or" the drum upon completion of a change of the signal fromstop to go.

5. A signaling device comprising a housing with a plurality of sides,each signaling side having a stop aperture and a go aperture; means forilluminating the apertures comprising a plurality of light sources foreach aperture; control means for said light sources including a rotaryinsulated drum having stepped contacts thereon; a plurality of fixedcontactors cooperating therewith upon rotation of the drum to controlthe illumination of said light sources in a predetermined manner duringa change of said signal; means for rotating the drum, including aperiodically operated motor and a slip coupling interposed loetween saidmotor and said drum; and means for limiting the amount of rotation ofthe drum for each operation of the motor, including aneletromagnetically operated latch which arrests rotation of the drumupon completion of the change of said signal from stop to go.

6. A signaling device comprising a housing with a plurality of sides,each signaling side having a stop aperture and a go aperture; means forilluminating the aperture comprising a plurality of light sources foreach aperture; control means for said light sources including a rotaryinsulated drum having stepped contacts thereon; a plurality of fixedcontactors cooperating therewith upon rotation of the drum to controlthe illumination of said light sources in a predetermined manner duringa change of said signal; a periodically operated motor, including africtional driving means for rotating the drum; and means for limitingthe amount of rotation of the drum, last-named means including a stopmeans associated with said drum, and an electromagnetir cally operatedlatch adapted to engage said stop means upon completion of each changeof the signal from stop to go.

'7. A signaling device comprising a housing and a plurality of sides,each signaling side having a stop aperture and a go aperture; means forilluminating 'the aperture, comprising a plurality of light sources foreach aperture; control means for said light sources, including a rotaryinsulated drum having stepped contacts thereon; a plurality of fixedcontactors cooperating therewith upon rotation of the drum to controlthe illumination of said light sources in a predetermined manner duringthe change of said signal; a periodically operated motor for rotatingthe drum to change the signal; a periodically energized circuittherefor; an electromagnetic means controlled by said circuit forarresting rotation of the drum upon completion of a change of saidsignal from stop to go during the period of rotation of the motor; andfrictional driving means between the motor and said drum, whereby saidmotor may overrun after operation of the electromagnetic means.

8. A signaling device comprising a housing and a plurality of sides,each signaling side having a stop aperture and a go aperture; means forilluminating the apertures comprising a plurality of light sources foreach aperture; control means for said light sources including a rotaryinsulated drum having stepped contacts thereon; a plurality of xedcontactors cooperating therewith upon rotation of the drum to controlthe illumination of sai-d light sources in a predetermined manner duringa change of said signal; means for arresting rotation of said drum uponcompletion of a change of said signal from stop to go; an intermittentlyoperated motor for rotating said drum; a circuit therefor including anelectro-magnetic means actuated by the initial surge of current throughsaid circuit upon energization of the motor, for releasing saidarresting means, and permitting rotation of the drum loy the motor forchanging the signal from stop -o go.

9. An intersection trailic signal comprising a frame having a pluralityof sides, each side having stop and go signals; means for illuminatingthe signals comprising a plurality of light sources to illuminate eachsignal, said means comprising at least two circuits, one of whichincludes the means for illuminating the stop signal for one traiiicdirection and the go signal for another traiiic direction, and anothercircuit including the means for illuminating the go signal for theformer and the stop signal for the latter tramo direction; means forcontrolling the illuminating means to indicate a change from stop to go,said means including a rotary contact drum having stepped contactsthereon; iixed contactors cooperating therewith upon rotation of thedrum to operate said circuits alternately, in each case firstilluminating all the light sources in the circuit and then extinguishingsaid sources on both the stop and go sides as the drum rotates; a motorfor rotating the drum operated during an interval for changing thesignal; and means for arresting rotation of said drum to preventoverrunning thereof upon illumination of all of the light sources ineither circuit.

10. A signaling device comprising a housing having a plurality of sides,each signaling side having a horizontal and vertical aperture, thehorizontal aperture giving a stop signal and the vertical aperturegiving a go signal; means for illuminating the signals, comprising aplurality of light sources to illuminate each of said apertures, saidmeans comprising at least two circuits, one of which includes the meansfor illuminating the stop signal for one traflic direction and the gosignal for another traflic direction, and the other circuit includingmeans for illuminating the go signal for the former and the stop signalfor the latter trafc direction; means for controlling the illuminatingmeans to indicate a change from stop to go, said means including arotary contact drum having stepped contacts thereon, fixed contactorscooperating with stepped, contacts to operate said circuits alternately,in each case first illuminating all the light sources in the circuit andthen extinguishing said sources in sequence on both the stop and gosides as the drum rotates; a motor for rotating the drum adapted to beoperated during an interval for changing the signal; and means forarresting rotation of said drum to prevent overrunning thereof uponillumination of all of the light sources in either circuit,

11. In a signaling device comprising a housing having a stop and a goaperture, a plurality of light sources for illuminating each aperture;

means for controlling said light sources in a predetermined mannerthroughout the period of changing of the signal to give a caution signalwhich indicates the extent of lapse of said changing period, saidcontrolling means including two relatively movable contact members, oneof which carries stepped contacts and the other carrying a plurality ofcontacts cooperating therewith to control the circuits of said lightsources in a predetermined manner upon relative motion of the contactmembers; driving means for eiecting relative motion of said contactmembers, periodically operated for changing said signal; an-delectro-responsive means for limiting the relative motion of saidmembers upon completion of a change of said signal from stop to go foreach periodic operation of said driving means.

12. In a signaling device comprising a housing having a stop and a goaperture, a plurality of light sources for illuminating each aperture;means for controlling said light sources in a predetermined mannerthroughout the period of changing of the signal to give a caution signalwhich indicates the extent of lapse of said changing period, saidcontrolling means including two relatively movable contact members, oneof which carries stepped contacts and the other carrying a plurality ofcontacts cooperating therewith to control the circuits of said lightsources in a predetermined manner upon relative motion of the contactmembers; electro-responsive driving means for effecting relative motionof said contact members, periodically operated to change said signal;and electro-responsive means for limiting the relative motion of saidmembers upon completion of a change .of said signal from stop to go foreach periodic operation of said electro-responsive driving means.

4 THEODORE E. STEIBER.

